Aphid alarm pheromone

Bowers, W.S., Nault, L.R., Webb, R.E. and Dutky, S.R. (1972) Aphid alarm pheromone isolation, idenfication, synthesis. Nature 177, 1121-1122. 

Beale MH, Birkett MA, Bmce TJA, Chamberlain K, Field LM, Huttly AK, Martin JL, Parker R, PhiUips AL, Pickett JA, Prosser IM, Shewry PR, Smart LE, Wadhams LJ, Woodcock CM, Zhang YH (2006) Aphid alarm pheromone produced by transgenic plants affects aphid and parasitoid behavior. Proc Nad Acad Sci USA 103 10509-10513... 

Ant (Acanthomyops claviger) defence (OD-R) [antiseptic, sedative] Aphid alarm pheromone... 

Aphid Alarm Pheromones. When aphids are attacked by predators they produce droplets of secretion from their cornicles whose odor initiates escape behavior in nearby siblings. The first alarm pheromone was identified by Bowers et al. (2A) for the rose, pea, greenbug, and cotton aphids as trans-0-farnesene. The macrocyclic hydrocarbon germacrene A was subsequently identified as the alarm pheromone of the sweetclover and spotted alfalfa aphids (Figure 6) (25., 25.). 

Nault LR, Montgomery ME, Bowers WS (1976) Ant-aphid association Role of aphid alarm pheromone. Science 192 1349-1350... 

Crock, J., Wildung, M. and Croteau, R. (1997) Isolation and bacterial expression of a sesquiterpene synthase cDNA clone from peppermint (Mentha x piperita, L.) that produces the aphid alarm pheromone (E)-beta-famesene. Proc. Natl. Acad. Sci. USA, 94, 12833-8. 

Aphid Alarm Pheromone. The alarm pheromone of aphids in the subfamily Aphidinae is ( )-P-famesene. The pheromone can be synthesized easily, but it is unstable under field conditions and therefore has limited potential for application. Although many plants produce this volatile chemical constitutively in their essential oil, aphids can differentiate between plant-produced material and aphid-produced material by the presence of other plant-derived terpenes, particularly ( )-caryophyllene, in the volatile blend. 

E-B-farnesene, an aphid alarm pheromone, was present in cv. Chippewa extracts, and made up one fourth of the total sesquiterpene content. In comparison, the E-B-farnesene in the S. berthaultii extract made up only one hundredth of the total sesquiterpene content. 

Pickett JA, Griffiths DC (1980) Composition of aphid alarm pheromones. J Chem Ecol 6 349-360 Ram JL, Mueller CT, Beckmann M, Hardege JD (1999) The spawning pheromone cysteine-glutathione disulfide ( Nereithione ) arouses a multicomponent nuptial behaviour and electro-... 

Gibson, R.W. Pickett, J.A. 1983. Wild potato repels aphids by release of aphid alarm pheromone. Miri/rg, 302, 608-609. 

Figure. 1. Nature of glandular trichome-mediated aphid resistance in 5. berthaultiL Key (1) Carboxylic acid sucrose esters (CASE), (2) Viscous type B trichome exudate, (3) Increased aphid movement and attempts to escape, (4) Adhesive aphid tarsi, (5) Enhanced rupture of type A trichome membrane , (6) Polyphenoloxidase + 02 + substrate, (7) Aphid alarm pheromone, E-(B)=famesene, (8) Encasement of tarsi by trichome exudate, (9) Greater effective tarsal size, (10) Decreased aphid mobility, (11) Occlusion of mouthparts by trichome exudate, (12) Starvation and death. Adapted from (38).

The receptors for aphid alarm pheromones are located on the antennae (Nault et al., 1973). Shambaugh et al. (1978) detailed the ultrastructure of potential alarm pheromone receptors in 17 aphid species. Excision of the terminal (6th) antennal segments of M. persicae, that bear the primary sensoria eliminated its response to alarm pheromone. Such excisions reduced but did not eliminate the response of A. pisum and Aulacarthum solani, both of which bear secondary sensoria on their 3rd antennal segments. Only removal of this segment eliminated response in these species. 

A reduction in alarm response is also observed when ants are attending the colony. Ants respond to the treehopper alarm pheromone with directed movements toward the source much as Formica subsericea attending aphids responds to aphid alarm pheromone (Nault et al.., 1976). When treehopper nymphs respond to the pheromone, ants increase their antennation of nymphs. Dorsal stroking slows movement of nymphs and its effectiveness is dependent on the amount of time spent stroking. Wood (1977) investigated the relative benefit of attendance by parent females vs. ants on survival of nymphs. Survival was always higher in colonies attended by either females or ants than in non-attended colonies. Survival of colonies attended by ants was not different than that of colonies attended by females until about 15 days after egg hatch. 

Bowers, W. S., Nishino, C., Montgomery, M. E. and Nault, L. R. (1977a) Structure-activity relationships of analogs of the aphid alarm pheromone, ( )-p-farnesene. J, Insect Physiol, 23, 697-701. 

Calabrese, E. J. and Sorensen, A. J. (1978) Dispersal and recolonization by Myzus persicae following aphid alarm pheromone exposure. Ann, ent, Soc, Am, 71, 181-2. 

Plant communication via volatile sesquiterpenes at the third trophic level, namral enemies of herbivores, has been shown in soil ecosystems. Root beetle damages on maize root system will induce production and emissions of ( )-p-caryophyllene, also known as an aphid alarm pheromone. This compound spreads through soil pores where it attracts entomopathogenic nematodes that, in turn, control root beetle larvae [13]. 

Ghosh M, Sinhababu SP, Sukul NC, Sahu NP, Mahato SB (1994) Antifilarial effect of solamargine isolated from Solanum khasianum. Int J Pharmacog 32 184-190 Gibson RW, Pickett JA (1983) Wild potato repels aphids by release of aphid alarm pheromone. Nature (London) 302 608-609... 

In contrast to sex and pheromones, where attraction is expected, the response to alarm pheromones depends on the social organization of the test species (Blum 1985). In noneusocial species, such as most aphids, alarm pheromones cause repellence, resulting in dispersal of the subjects. Thus, in principle, the major difference in bioassays between sex pheromones and alarm pheromones for these species is the direction of expected displacement relative to the source. While complex wind tunnels have been used in bioassays for alarm pheromones (e.g., Phelan Miller 1982), the presence and identity of alarm pheromones often can be determined with relatively simple equipment. 

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